Under Mac OS X Version 10.6.8, I ran "frama-c-gui -val exm02.c" on the attached program. In the "Messages" window of the Frama-C gui, an overflow warning is displayed for line 4, which is ok.

After clicking on the "Reparse" button, that message disappears, although nothing has been changed in the source code. Even after clicking on the "Analyses" button and clicking on the "Execute" button in the popped-up window "Launching analysis", the overflow warning doesn't appear again.

This is actually a bug in the memoization of messages, which is not currently project-aware; the message is not re-emitted on the console either. Admittedly, we can improve at least the behavior of the reparse button.